Cesar M Moreira | ESPOL (Escuela Superior Politécnica del Litoral) (original) (raw)
Papers by Cesar M Moreira
Procedia CIRP, 2020
Transition towards a more sustainable society is a complex task. The depletion of natural resourc... more Transition towards a more sustainable society is a complex task. The depletion of natural resources and waste generation cannot be sustained indefinitely, i.e. as waste increases, local landfills keep growing and land availability reduces. The introduction of circular economy in effective household solid waste management practices should be considered especially for third world countries, such as Ecuador. In this context, plastic recycling is an important step, particularly the case of expanded polystyrene containers that currently are single-use only and later end up in local landfills. This paper presents a methodology for recycling Expanded Polystyrene by means of a case study from an Ecuadorian Plastic Manufacturer. First, the manufacture of resin from post-consume EPS containers was demonstrated possible by the manufacturer. Second, results show that using 30% of post-consume resin in the mix produce satisfactory laboratory results and operational recycled containers.
Nine microalgae strains were collected, identified, isolated, and cultured under laboratory condi... more Nine microalgae strains were collected, identified, isolated, and cultured under laboratory conditions in pretreated domestic wastewater (WW) at 30°C and 40°C using 12:12 photoperiod. The 3 strains with better growth rate, i.e., Chlorella sp. M2, Chlorella sp. M6 and Scenedesmus sp. R3 were selected to grow outdoors on partially aerobically treated WW in two types of photo-bioreactors: cylinder and panel. The cultures were harvested when they reached stationary phase and then dried. Chlorella sp. M2 presented the highest growth rate, moisture content, total lipids, carbohydrates, and total polyphenols. Chlorella sp. M6 showed the highest ash content and antioxidant capacity, while Scenedesmus sp. R3 had the highest protein content. There were significant differences among strains in terms of ashes, lipids, proteins, carbohydrates, total polyphenols, and antioxidant capacity. Additionally, the type of photobioreactor influenced the amount of lipids, proteins, carbohydrates, and the antioxidant capacity of algal strains. The strains presented absorbance in the wavelengths of the phytopigments astaxanthin, lutein, neoxanthin, ɑ-carotene, β-carotene, and δ-carotene. The native microalga Chlorella sp. M2, regardless of the method of cultivation, was the one with the best source of macronutrients and polyphenols; meanwhile, the panel-type photo bioreactor was the most effective for cultivating microalgae for phytopigments.
Conference: The 16th LACCEI International Multi-Conference for Engineering, Education, and Technology: “Innovation in Education and Inclusion, 2018
— The present work is based in a study starting from the behavior and characterization of films m... more — The present work is based in a study starting from the behavior and characterization of films made from a 2% total solids (TS) dispersion of easy accessibility raw materials such as, cassava starch (Y), potato (P) and rice (A), combined with a protein i.e. gelatin (G) in a 50:50 ratio; adding guaiacum wood fiber of 75 and 150 µm (Ff and Fg respectively) until 1% (TS). Furthermore, glycerol was incorporated as plasticizer until 30% TS. The biodegradable films were elaborated by casting method. The films were characterized on the following parameters: thickness, water permeability and mechanical properties (Young modulus, tensile stress and elongation). It was found that the films made of AG-Ff and PG-Ff shown better barrier to the water vapor permeability with values of 2.5 and 2.4 (g. mm. KPa-1. h-1 .m 2) respectively. The PG-Ff film showed, also, better mechanical properties i.e. higher Force, Young modulus and tensile stress increasing with time, with the lower elasticity; the YG-Ff and YG-Fg films reported the higher elasticity, being this parameter of interest, we will continue with this formulae to other manufacturing processes.
). Thereafter, bags were made using the casted films, and used to pack peanuts; moisture levels w... more ). Thereafter, bags were made using the casted films, and used to pack peanuts; moisture levels were measured after 10, 20, 40 and 60 days. Results suggested that there was not significant difference among them, the peanuts shown a final moisture value of 7.4%, being the limit of moisture for peanuts 9%. This result justifies the application of the obtained film as a food packaging due to its characteristic of good barrier for water vapor therefore protecting the food stuff. . Thereafter, bags were made using the casted films, and used to pack peanuts; moisture levels were measured after 10, 20, 40 and 60 days. Results suggested that there was not significant difference among them, the peanuts shown a final moisture value of 7.4%, being the limit of moisture for peanuts 9%. This result justifies the application of the obtained film as a food packaging due to its characteristic of good barrier for water vapor therefore protecting the food stuff.
–Thermal treatment of 2.5 grams (dry weight) and 7.5 grams (dry weight) batches of Polylactic aci... more –Thermal treatment of 2.5 grams (dry weight) and 7.5 grams (dry weight) batches of Polylactic acid (PLA)-product waste was carried out at 121 oC and 160 oC and exposed to different treatment time periods. Molecular weight reduction was not affected by the amount of PLA material loaded. Rate of molecular weight reduction was about six times faster at 160 oC than at 121 oC. Complete depolymerization of the PLA-product waste was not possible at the temperatures used here. A maximum recovery (yield) of lactic acid of 35% was obtained at a loading of 7.5 g, temperature at 121 °C and exposure time of 720 min. At 160°C , recovery was 25% but obtained within 120 minutes. Results suggest that PLA-product waste behaviour will differ from pure PLA pellet. With PLA-product waste complete lactic acid recovery was not possible and other by-products like acetic and propionic acids were produced from thermal treatment. Keywords—Steam hydrolysis, PLA, first order kinetics, lactic acid Digital Object Identifier (DOI): Abstract–Thermal treatment of 2.5 grams (dry weight) and 7.5 grams (dry weight) batches of Polylactic acid (PLA)-product waste was carried out at 121 o C and 160 o C and exposed to different treatment time periods. Molecular weight reduction was not affected by the amount of PLA material loaded. Rate of molecular weight reduction was about six times faster at 160 o C than at 121 o C. Complete depolymerization of the PLA-product waste was not possible at the temperatures used here. A maximum recovery (yield) of lactic acid of 35% was obtained at a loading of 7.5 g, temperature at 121 °C and exposure time of 720 min. At 160°C , recovery was 25% but obtained within 120 minutes. Results suggest that PLA-product waste behaviour will differ from pure PLA pellet. With PLA-product waste complete lactic acid recovery was not possible and other by-products like acetic and propionic acids were produced from thermal treatment.
– There are numerous benefits of using anaerobic digestion to treat organic wastes. Anaerobic dig... more – There are numerous benefits of using anaerobic digestion to treat organic wastes. Anaerobic digestion to treat sugar beet scrap materials has been proven as an effective alternative to landfilling. Byproducts of the anaerobic digestion process are liquid effluent and volume-reduced sludge. It is proposed that liquid effluent and sludge can be placed on arable lands. In order to return these byproducts, noxious weed seeds that may enter the digestion process must be eradicated in the process. This study was undertaken to determine if five species of noxious weeds seeds would be destroyed by anaerobic digestion. Small batch anaerobic digesters were made to study its effect on five weed species. The digestion lasted for 10 days and was performed at 55 ºC. Five additional samples were used to determine the effects of warm water on the seeds. In addition, five dry containers with dry seeds were incubated to determine the effects of dry heat. Results showed that both anaerobic digestion leachate and warm water caused seed destruction for the all seeds compared to dry heat treatment or no treatment. A secondary observation showed that fungal growth was inhibited by anaerobic digestion. Abstract– There are numerous benefits of using anaerobic digestion to treat organic wastes. Anaerobic digestion to treat sugar beet scrap materials has been proven as an effective alternative to landfilling. Byproducts of the anaerobic digestion process are liquid effluent and volume-reduced sludge. It is proposed that liquid effluent and sludge can be placed on arable lands. In order to return these byproducts, noxious weed seeds that may enter the digestion process must be eradicated in the process. This study was undertaken to determine if five species of noxious weeds seeds would be destroyed by anaerobic digestion. Small batch anaerobic digesters were made to study its effect on five weed species. The digestion lasted for 10 days and was performed at 55 ºC. Five additional samples were used to determine the effects of warm water on the seeds. In addition, five dry containers with dry seeds were incubated to determine the effects of dry heat. Results showed that both anaerobic digestion leachate and warm water caused seed destruction for the all seeds compared to dry heat treatment or no treatment. A secondary observation showed that fungal growth was inhibited by anaerobic digestion.
We present our investigation of using microfluidic devices for rapid protein separation. The devi... more We present our investigation of using microfluidic devices for rapid protein separation. The devices were made from cyclic olefin copolymers that have high optical clarity and high glass transition temperature. Protein separation was achieved by using isoelectric focusing (IEF) and polyacrylamide gel electrophoresis (PAGE). A laser-induced fluorescence (LIF) imaging system was developed to detect proteins while they migrated under an electric field. IEF was carried out in a separation medium consisting of carrier ampholytes and a mixture of linear polymers. Dynamic coating of the linear polymers prevented proteins from adsorption and suppressed electroosmotic flows. PAGE was achieved in twenty-nine parallel channels. In addition, we integrated IEF with PAGE in a microfluidic device for two-dimensional protein separation.
Tropical and sub-tropical countries grow bananas in large quantities. About 13% by weight of the ... more Tropical and sub-tropical countries grow bananas in large quantities. About 13% by weight of the harvested banana cluster is banana peduncle waste, usually discarded or composted. The feasibility of using this waste as a feedstock to produce biofuels like ethanol and biogas was evaluated. Commercially available equipment was used to crush the peduncle, resulting in 0.591 g of juice/g fresh peduncle composed of glucose (7 g/L), sucrose (3 g/L) and fructose (8 g/L). Five-day fermentation of five times concentrated peduncle extract yielded 0.41 g ethanol/ g sugars, without need for any additional nutrient for fermentation; higher concentrations were inhibitory. Additionally, the residual bagasse after extraction and stillage (after ethanol distillation), was successfully anaerobically digested to produce biogas. The methane yields were 0.263 L methane at standard temperature and pressure (STP)/g volatile solids (VS) of bagasse, and 0.08 L methane at STP/g VS stillage which resolves approximately 68% of energy requirements for the concentration step. In Ecuador, about 4 million liters of ethanol can be produced from peduncle. It is envisaged that the concentrated syrup can be prepared at the packing house using biogas from peduncle bagasse as fuel, then dispatched to an ethanolprocessing central facility.
– An anaerobic digestion system that was completely operated on solar power (both photovoltaic an... more – An anaerobic digestion system that was completely operated on solar power (both photovoltaic and solar thermal energy), and mounted on a trailer to make it mobile, was designed and constructed. A 55-gallon batch digester was placed within a chamber that was heated by hot water pumped through a radiator. Hot water was produced by a solar thermal collector and photovoltaic panels charged a battery which operated pumps for recirculating water. It was found that the temperature in the heating chamber was maintained above ambient temperature but it follows the same trend as ambient temperature. The temperature difference between the chamber and ambient values was not constant but varied with time of day. Advantageously, the temperature difference was highest during night and early morning and lowest near noon. In winter when ambient temperature dipped to 2 °C during early morning hours, the chamber temperature did not drop below 10 °C. Model simulations showed that even if the digester is subjected to diurnal variations of temperature (as observed in winter of a subtropical region), about 63 % of the waste that would have been processed under constant digester temperature of 38 °C, can still be processed. The cost of the digester system without the trailer was 1,800Abstract–Ananaerobicdigestionsystemthatwascompletelyoperatedonsolarpower(bothphotovoltaicandsolarthermalenergy),andmountedonatrailertomakeitmobile,wasdesignedandconstructed.A55−gallonbatchdigesterwasplacedwithinachamberthatwasheatedbyhotwaterpumpedthrougharadiator.Hotwaterwasproducedbyasolarthermalcollectorandphotovoltaicpanelschargedabatterywhichoperatedpumpsforrecirculatingwater.Itwasfoundthatthetemperatureintheheatingchamberwasmaintainedaboveambienttemperaturebutitfollowsthesametrendasambienttemperature.Thetemperaturedifferencebetweenthechamberandambientvalueswasnotconstantbutvariedwithtimeofday.Advantageously,thetemperaturedifferencewashighestduringnightandearlymorningandlowestnearnoon.Inwinterwhenambienttemperaturedippedto2°Cduringearlymorninghours,thechambertemperaturedidnotdropbelow10°C.Modelsimulationsshowedthatevenifthedigesterissubjectedtodiurnalvariationsoftemperature(asobservedinwinterofasubtropicalregion),about631,800 Abstract– An anaerobic digestion system that was completely operated on solar power (both photovoltaic and solar thermal energy), and mounted on a trailer to make it mobile, was designed and constructed. A 55-gallon batch digester was placed within a chamber that was heated by hot water pumped through a radiator. Hot water was produced by a solar thermal collector and photovoltaic panels charged a battery which operated pumps for recirculating water. It was found that the temperature in the heating chamber was maintained above ambient temperature but it follows the same trend as ambient temperature. The temperature difference between the chamber and ambient values was not constant but varied with time of day. Advantageously, the temperature difference was highest during night and early morning and lowest near noon. In winter when ambient temperature dipped to 2 °C during early morning hours, the chamber temperature did not drop below 10 °C. Model simulations showed that even if the digester is subjected to diurnal variations of temperature (as observed in winter of a subtropical region), about 63 % of the waste that would have been processed under constant digester temperature of 38 °C, can still be processed. The cost of the digester system without the trailer was 1,800Abstract–Ananaerobicdigestionsystemthatwascompletelyoperatedonsolarpower(bothphotovoltaicandsolarthermalenergy),andmountedonatrailertomakeitmobile,wasdesignedandconstructed.A55−gallonbatchdigesterwasplacedwithinachamberthatwasheatedbyhotwaterpumpedthrougharadiator.Hotwaterwasproducedbyasolarthermalcollectorandphotovoltaicpanelschargedabatterywhichoperatedpumpsforrecirculatingwater.Itwasfoundthatthetemperatureintheheatingchamberwasmaintainedaboveambienttemperaturebutitfollowsthesametrendasambienttemperature.Thetemperaturedifferencebetweenthechamberandambientvalueswasnotconstantbutvariedwithtimeofday.Advantageously,thetemperaturedifferencewashighestduringnightandearlymorningandlowestnearnoon.Inwinterwhenambienttemperaturedippedto2°Cduringearlymorninghours,thechambertemperaturedidnotdropbelow10°C.Modelsimulationsshowedthatevenifthedigesterissubjectedtodiurnalvariationsoftemperature(asobservedinwinterofasubtropicalregion),about631,800
– The present study comprises the analysis, design and construction of a domestic stove gasifier ... more – The present study comprises the analysis, design and construction of a domestic stove gasifier for rural communities, the unit utilizes local residual biomass available in Ecuador's Zone 8 as a fuel. During the analysis, literature was consulted in order to avoid common known problems presented in this kind of stoves. Aditionally, it has been considered multiple design criteria and heat transfer analysis. Importantly, for the construction, local materials has been used to keep costs low and increment its accessability. Throughout the evaluation of the stove gasifier several experiments using the local available biomass were run (rice husks, dry branches and litterfall). The best results were obtained when using agroforestal residues, i.e. a blend of 90% dry branches and 10% litterfall. However, a problem of compaction was detected when using rice husks; this compaction lead to a poor combustión and excess of smoke. To prevent compaction leaves was used as a bulking material. The results suggested that the best blend when working with rice husks was a mix of 20% rice husks and 80% of litterfall, higher concentrations of rice husks will result in excesive amounts of smoke and poor combustion. Finally, the designed stove gasifier works well, if the used biomass does not go through compaction. Therefore, it can be used in rural villages as an alternative for cooking Keywords-biomass, rice husks , stove, gasifier, litterfall. Resumen— El presente estudio está relacionado al diseño, análisis y construcción de una estufa domestica para comunidades rurales, utilizando como combustible principal la biomasa sólida residual disponible en la zona 8 del Ecuador, es decir, biomasa proveniente del sector arrocero, podas, cañeras, hojarasca, entre otros. Durante el análisis, se consultó literatura disponible con el fin de evitar problemas comunes que se presentan en tipo de estufas. Adicionalmente, se ha considerado varios criterios de diseño y análisis de transferencia de calor. Es importante destacar que, para diseñar una estufa de bajo costo e incrementar su accesibilidad, se ha utilizado para la construcción del equipo material disponibles de la zona. Durante la etapa de evaluación de la estufa gasificadora se realizaron varios experimentos usando la biomasa disponible localmente (cascarilla de arroz, ramas secas y hojarasca). Los mejores resultados se obtuvieron con mezclas de residuos agroforestales, específicamente, una mezcla de 90% ramas secas y 10% de hojarasca. Por otra parte, se detectó problemas de compactación al utilizar el 100 % de la cascarilla de arroz; esta compactación conduce a una mala combustión y exceso de humo. Para evitar el problema de compactación, se decidió incrementar la densidad aparente utilizando como mezclas hojarasca. Es así, que los resultados sugieren que al trabajar con cascarilla de arroz se realicen mezclas del 20% cascarilla con el 80% hojarasca. Esto es debido que en concentraciones mayores de cascarilla de arroz dan lugar a cantidades excesivas de humo y una mala combustión. Finalmente, podemos indicar que se ha diseñado una estufa gasificadora que mantiene una combustión controlada sin emisión de gases contaminantes, siempre que la biomasa utilizada no pasa por la compactación. Por lo tanto, se puede utilizar en la zona rural como una alternativa para cocinar. Palabras Claves— biomasa, cascarilla de arroz, estufa, gasificadora, hojarasca
Procedia CIRP, 2020
Transition towards a more sustainable society is a complex task. The depletion of natural resourc... more Transition towards a more sustainable society is a complex task. The depletion of natural resources and waste generation cannot be sustained indefinitely, i.e. as waste increases, local landfills keep growing and land availability reduces. The introduction of circular economy in effective household solid waste management practices should be considered especially for third world countries, such as Ecuador. In this context, plastic recycling is an important step, particularly the case of expanded polystyrene containers that currently are single-use only and later end up in local landfills. This paper presents a methodology for recycling Expanded Polystyrene by means of a case study from an Ecuadorian Plastic Manufacturer. First, the manufacture of resin from post-consume EPS containers was demonstrated possible by the manufacturer. Second, results show that using 30% of post-consume resin in the mix produce satisfactory laboratory results and operational recycled containers.
Nine microalgae strains were collected, identified, isolated, and cultured under laboratory condi... more Nine microalgae strains were collected, identified, isolated, and cultured under laboratory conditions in pretreated domestic wastewater (WW) at 30°C and 40°C using 12:12 photoperiod. The 3 strains with better growth rate, i.e., Chlorella sp. M2, Chlorella sp. M6 and Scenedesmus sp. R3 were selected to grow outdoors on partially aerobically treated WW in two types of photo-bioreactors: cylinder and panel. The cultures were harvested when they reached stationary phase and then dried. Chlorella sp. M2 presented the highest growth rate, moisture content, total lipids, carbohydrates, and total polyphenols. Chlorella sp. M6 showed the highest ash content and antioxidant capacity, while Scenedesmus sp. R3 had the highest protein content. There were significant differences among strains in terms of ashes, lipids, proteins, carbohydrates, total polyphenols, and antioxidant capacity. Additionally, the type of photobioreactor influenced the amount of lipids, proteins, carbohydrates, and the antioxidant capacity of algal strains. The strains presented absorbance in the wavelengths of the phytopigments astaxanthin, lutein, neoxanthin, ɑ-carotene, β-carotene, and δ-carotene. The native microalga Chlorella sp. M2, regardless of the method of cultivation, was the one with the best source of macronutrients and polyphenols; meanwhile, the panel-type photo bioreactor was the most effective for cultivating microalgae for phytopigments.
Conference: The 16th LACCEI International Multi-Conference for Engineering, Education, and Technology: “Innovation in Education and Inclusion, 2018
— The present work is based in a study starting from the behavior and characterization of films m... more — The present work is based in a study starting from the behavior and characterization of films made from a 2% total solids (TS) dispersion of easy accessibility raw materials such as, cassava starch (Y), potato (P) and rice (A), combined with a protein i.e. gelatin (G) in a 50:50 ratio; adding guaiacum wood fiber of 75 and 150 µm (Ff and Fg respectively) until 1% (TS). Furthermore, glycerol was incorporated as plasticizer until 30% TS. The biodegradable films were elaborated by casting method. The films were characterized on the following parameters: thickness, water permeability and mechanical properties (Young modulus, tensile stress and elongation). It was found that the films made of AG-Ff and PG-Ff shown better barrier to the water vapor permeability with values of 2.5 and 2.4 (g. mm. KPa-1. h-1 .m 2) respectively. The PG-Ff film showed, also, better mechanical properties i.e. higher Force, Young modulus and tensile stress increasing with time, with the lower elasticity; the YG-Ff and YG-Fg films reported the higher elasticity, being this parameter of interest, we will continue with this formulae to other manufacturing processes.
). Thereafter, bags were made using the casted films, and used to pack peanuts; moisture levels w... more ). Thereafter, bags were made using the casted films, and used to pack peanuts; moisture levels were measured after 10, 20, 40 and 60 days. Results suggested that there was not significant difference among them, the peanuts shown a final moisture value of 7.4%, being the limit of moisture for peanuts 9%. This result justifies the application of the obtained film as a food packaging due to its characteristic of good barrier for water vapor therefore protecting the food stuff. . Thereafter, bags were made using the casted films, and used to pack peanuts; moisture levels were measured after 10, 20, 40 and 60 days. Results suggested that there was not significant difference among them, the peanuts shown a final moisture value of 7.4%, being the limit of moisture for peanuts 9%. This result justifies the application of the obtained film as a food packaging due to its characteristic of good barrier for water vapor therefore protecting the food stuff.
–Thermal treatment of 2.5 grams (dry weight) and 7.5 grams (dry weight) batches of Polylactic aci... more –Thermal treatment of 2.5 grams (dry weight) and 7.5 grams (dry weight) batches of Polylactic acid (PLA)-product waste was carried out at 121 oC and 160 oC and exposed to different treatment time periods. Molecular weight reduction was not affected by the amount of PLA material loaded. Rate of molecular weight reduction was about six times faster at 160 oC than at 121 oC. Complete depolymerization of the PLA-product waste was not possible at the temperatures used here. A maximum recovery (yield) of lactic acid of 35% was obtained at a loading of 7.5 g, temperature at 121 °C and exposure time of 720 min. At 160°C , recovery was 25% but obtained within 120 minutes. Results suggest that PLA-product waste behaviour will differ from pure PLA pellet. With PLA-product waste complete lactic acid recovery was not possible and other by-products like acetic and propionic acids were produced from thermal treatment. Keywords—Steam hydrolysis, PLA, first order kinetics, lactic acid Digital Object Identifier (DOI): Abstract–Thermal treatment of 2.5 grams (dry weight) and 7.5 grams (dry weight) batches of Polylactic acid (PLA)-product waste was carried out at 121 o C and 160 o C and exposed to different treatment time periods. Molecular weight reduction was not affected by the amount of PLA material loaded. Rate of molecular weight reduction was about six times faster at 160 o C than at 121 o C. Complete depolymerization of the PLA-product waste was not possible at the temperatures used here. A maximum recovery (yield) of lactic acid of 35% was obtained at a loading of 7.5 g, temperature at 121 °C and exposure time of 720 min. At 160°C , recovery was 25% but obtained within 120 minutes. Results suggest that PLA-product waste behaviour will differ from pure PLA pellet. With PLA-product waste complete lactic acid recovery was not possible and other by-products like acetic and propionic acids were produced from thermal treatment.
– There are numerous benefits of using anaerobic digestion to treat organic wastes. Anaerobic dig... more – There are numerous benefits of using anaerobic digestion to treat organic wastes. Anaerobic digestion to treat sugar beet scrap materials has been proven as an effective alternative to landfilling. Byproducts of the anaerobic digestion process are liquid effluent and volume-reduced sludge. It is proposed that liquid effluent and sludge can be placed on arable lands. In order to return these byproducts, noxious weed seeds that may enter the digestion process must be eradicated in the process. This study was undertaken to determine if five species of noxious weeds seeds would be destroyed by anaerobic digestion. Small batch anaerobic digesters were made to study its effect on five weed species. The digestion lasted for 10 days and was performed at 55 ºC. Five additional samples were used to determine the effects of warm water on the seeds. In addition, five dry containers with dry seeds were incubated to determine the effects of dry heat. Results showed that both anaerobic digestion leachate and warm water caused seed destruction for the all seeds compared to dry heat treatment or no treatment. A secondary observation showed that fungal growth was inhibited by anaerobic digestion. Abstract– There are numerous benefits of using anaerobic digestion to treat organic wastes. Anaerobic digestion to treat sugar beet scrap materials has been proven as an effective alternative to landfilling. Byproducts of the anaerobic digestion process are liquid effluent and volume-reduced sludge. It is proposed that liquid effluent and sludge can be placed on arable lands. In order to return these byproducts, noxious weed seeds that may enter the digestion process must be eradicated in the process. This study was undertaken to determine if five species of noxious weeds seeds would be destroyed by anaerobic digestion. Small batch anaerobic digesters were made to study its effect on five weed species. The digestion lasted for 10 days and was performed at 55 ºC. Five additional samples were used to determine the effects of warm water on the seeds. In addition, five dry containers with dry seeds were incubated to determine the effects of dry heat. Results showed that both anaerobic digestion leachate and warm water caused seed destruction for the all seeds compared to dry heat treatment or no treatment. A secondary observation showed that fungal growth was inhibited by anaerobic digestion.
We present our investigation of using microfluidic devices for rapid protein separation. The devi... more We present our investigation of using microfluidic devices for rapid protein separation. The devices were made from cyclic olefin copolymers that have high optical clarity and high glass transition temperature. Protein separation was achieved by using isoelectric focusing (IEF) and polyacrylamide gel electrophoresis (PAGE). A laser-induced fluorescence (LIF) imaging system was developed to detect proteins while they migrated under an electric field. IEF was carried out in a separation medium consisting of carrier ampholytes and a mixture of linear polymers. Dynamic coating of the linear polymers prevented proteins from adsorption and suppressed electroosmotic flows. PAGE was achieved in twenty-nine parallel channels. In addition, we integrated IEF with PAGE in a microfluidic device for two-dimensional protein separation.
Tropical and sub-tropical countries grow bananas in large quantities. About 13% by weight of the ... more Tropical and sub-tropical countries grow bananas in large quantities. About 13% by weight of the harvested banana cluster is banana peduncle waste, usually discarded or composted. The feasibility of using this waste as a feedstock to produce biofuels like ethanol and biogas was evaluated. Commercially available equipment was used to crush the peduncle, resulting in 0.591 g of juice/g fresh peduncle composed of glucose (7 g/L), sucrose (3 g/L) and fructose (8 g/L). Five-day fermentation of five times concentrated peduncle extract yielded 0.41 g ethanol/ g sugars, without need for any additional nutrient for fermentation; higher concentrations were inhibitory. Additionally, the residual bagasse after extraction and stillage (after ethanol distillation), was successfully anaerobically digested to produce biogas. The methane yields were 0.263 L methane at standard temperature and pressure (STP)/g volatile solids (VS) of bagasse, and 0.08 L methane at STP/g VS stillage which resolves approximately 68% of energy requirements for the concentration step. In Ecuador, about 4 million liters of ethanol can be produced from peduncle. It is envisaged that the concentrated syrup can be prepared at the packing house using biogas from peduncle bagasse as fuel, then dispatched to an ethanolprocessing central facility.
– An anaerobic digestion system that was completely operated on solar power (both photovoltaic an... more – An anaerobic digestion system that was completely operated on solar power (both photovoltaic and solar thermal energy), and mounted on a trailer to make it mobile, was designed and constructed. A 55-gallon batch digester was placed within a chamber that was heated by hot water pumped through a radiator. Hot water was produced by a solar thermal collector and photovoltaic panels charged a battery which operated pumps for recirculating water. It was found that the temperature in the heating chamber was maintained above ambient temperature but it follows the same trend as ambient temperature. The temperature difference between the chamber and ambient values was not constant but varied with time of day. Advantageously, the temperature difference was highest during night and early morning and lowest near noon. In winter when ambient temperature dipped to 2 °C during early morning hours, the chamber temperature did not drop below 10 °C. Model simulations showed that even if the digester is subjected to diurnal variations of temperature (as observed in winter of a subtropical region), about 63 % of the waste that would have been processed under constant digester temperature of 38 °C, can still be processed. The cost of the digester system without the trailer was 1,800Abstract–Ananaerobicdigestionsystemthatwascompletelyoperatedonsolarpower(bothphotovoltaicandsolarthermalenergy),andmountedonatrailertomakeitmobile,wasdesignedandconstructed.A55−gallonbatchdigesterwasplacedwithinachamberthatwasheatedbyhotwaterpumpedthrougharadiator.Hotwaterwasproducedbyasolarthermalcollectorandphotovoltaicpanelschargedabatterywhichoperatedpumpsforrecirculatingwater.Itwasfoundthatthetemperatureintheheatingchamberwasmaintainedaboveambienttemperaturebutitfollowsthesametrendasambienttemperature.Thetemperaturedifferencebetweenthechamberandambientvalueswasnotconstantbutvariedwithtimeofday.Advantageously,thetemperaturedifferencewashighestduringnightandearlymorningandlowestnearnoon.Inwinterwhenambienttemperaturedippedto2°Cduringearlymorninghours,thechambertemperaturedidnotdropbelow10°C.Modelsimulationsshowedthatevenifthedigesterissubjectedtodiurnalvariationsoftemperature(asobservedinwinterofasubtropicalregion),about631,800 Abstract– An anaerobic digestion system that was completely operated on solar power (both photovoltaic and solar thermal energy), and mounted on a trailer to make it mobile, was designed and constructed. A 55-gallon batch digester was placed within a chamber that was heated by hot water pumped through a radiator. Hot water was produced by a solar thermal collector and photovoltaic panels charged a battery which operated pumps for recirculating water. It was found that the temperature in the heating chamber was maintained above ambient temperature but it follows the same trend as ambient temperature. The temperature difference between the chamber and ambient values was not constant but varied with time of day. Advantageously, the temperature difference was highest during night and early morning and lowest near noon. In winter when ambient temperature dipped to 2 °C during early morning hours, the chamber temperature did not drop below 10 °C. Model simulations showed that even if the digester is subjected to diurnal variations of temperature (as observed in winter of a subtropical region), about 63 % of the waste that would have been processed under constant digester temperature of 38 °C, can still be processed. The cost of the digester system without the trailer was 1,800Abstract–Ananaerobicdigestionsystemthatwascompletelyoperatedonsolarpower(bothphotovoltaicandsolarthermalenergy),andmountedonatrailertomakeitmobile,wasdesignedandconstructed.A55−gallonbatchdigesterwasplacedwithinachamberthatwasheatedbyhotwaterpumpedthrougharadiator.Hotwaterwasproducedbyasolarthermalcollectorandphotovoltaicpanelschargedabatterywhichoperatedpumpsforrecirculatingwater.Itwasfoundthatthetemperatureintheheatingchamberwasmaintainedaboveambienttemperaturebutitfollowsthesametrendasambienttemperature.Thetemperaturedifferencebetweenthechamberandambientvalueswasnotconstantbutvariedwithtimeofday.Advantageously,thetemperaturedifferencewashighestduringnightandearlymorningandlowestnearnoon.Inwinterwhenambienttemperaturedippedto2°Cduringearlymorninghours,thechambertemperaturedidnotdropbelow10°C.Modelsimulationsshowedthatevenifthedigesterissubjectedtodiurnalvariationsoftemperature(asobservedinwinterofasubtropicalregion),about631,800
– The present study comprises the analysis, design and construction of a domestic stove gasifier ... more – The present study comprises the analysis, design and construction of a domestic stove gasifier for rural communities, the unit utilizes local residual biomass available in Ecuador's Zone 8 as a fuel. During the analysis, literature was consulted in order to avoid common known problems presented in this kind of stoves. Aditionally, it has been considered multiple design criteria and heat transfer analysis. Importantly, for the construction, local materials has been used to keep costs low and increment its accessability. Throughout the evaluation of the stove gasifier several experiments using the local available biomass were run (rice husks, dry branches and litterfall). The best results were obtained when using agroforestal residues, i.e. a blend of 90% dry branches and 10% litterfall. However, a problem of compaction was detected when using rice husks; this compaction lead to a poor combustión and excess of smoke. To prevent compaction leaves was used as a bulking material. The results suggested that the best blend when working with rice husks was a mix of 20% rice husks and 80% of litterfall, higher concentrations of rice husks will result in excesive amounts of smoke and poor combustion. Finally, the designed stove gasifier works well, if the used biomass does not go through compaction. Therefore, it can be used in rural villages as an alternative for cooking Keywords-biomass, rice husks , stove, gasifier, litterfall. Resumen— El presente estudio está relacionado al diseño, análisis y construcción de una estufa domestica para comunidades rurales, utilizando como combustible principal la biomasa sólida residual disponible en la zona 8 del Ecuador, es decir, biomasa proveniente del sector arrocero, podas, cañeras, hojarasca, entre otros. Durante el análisis, se consultó literatura disponible con el fin de evitar problemas comunes que se presentan en tipo de estufas. Adicionalmente, se ha considerado varios criterios de diseño y análisis de transferencia de calor. Es importante destacar que, para diseñar una estufa de bajo costo e incrementar su accesibilidad, se ha utilizado para la construcción del equipo material disponibles de la zona. Durante la etapa de evaluación de la estufa gasificadora se realizaron varios experimentos usando la biomasa disponible localmente (cascarilla de arroz, ramas secas y hojarasca). Los mejores resultados se obtuvieron con mezclas de residuos agroforestales, específicamente, una mezcla de 90% ramas secas y 10% de hojarasca. Por otra parte, se detectó problemas de compactación al utilizar el 100 % de la cascarilla de arroz; esta compactación conduce a una mala combustión y exceso de humo. Para evitar el problema de compactación, se decidió incrementar la densidad aparente utilizando como mezclas hojarasca. Es así, que los resultados sugieren que al trabajar con cascarilla de arroz se realicen mezclas del 20% cascarilla con el 80% hojarasca. Esto es debido que en concentraciones mayores de cascarilla de arroz dan lugar a cantidades excesivas de humo y una mala combustión. Finalmente, podemos indicar que se ha diseñado una estufa gasificadora que mantiene una combustión controlada sin emisión de gases contaminantes, siempre que la biomasa utilizada no pasa por la compactación. Por lo tanto, se puede utilizar en la zona rural como una alternativa para cocinar. Palabras Claves— biomasa, cascarilla de arroz, estufa, gasificadora, hojarasca